1. Field of the Invention
This invention relates to an alarm horn such as a fire alarm or a burglar alarm.
2. Prior Art
One conventional alarm horn 10 shown in FIG. 1 comprises a casing 12 of cast aluminum or a molded synthetic resin having an end wall 12a and an open end 12b, a sound-generating unit 14 mounted within the casing 12 and having a first horn 14a, a second horn 16 secured to a base 14b of the sound-generating unit 14 by screws 13 in enclosing relation to the first horn 14a, and a third horn 18 engaged with the base 14b and an inner peripheral surface of the casing 12 at opposite ends thereof, the third horn 18 being secured to the base 14b by screws 15. The sound-generating unit 14 is in the form of a dynamic loudspeaker. The end wall 12a of the casing 12 has a plurality of apertures 12b therethrough for transmitting the sound, generated by the sound-generating unit 14, to the exterior of the casing 12. A lid 17 is attached to the open end 12b of the casing 12, and the base 14b of the sound-generating unit 14 is secured to the lid 17 by screws 19. Thus, the sound-generating unit 14, the second and third horns 16 and 18 and the casing 12 are fixed with respect to one another by screws 13, 15 and 19. With this construction, the conventional alarm horn 10 has often suffered from the disadvantage that unless the component parts are connected together firmly to provide a sufficient strength, the alarm horn 10 is subjected to damage when subjected to severe external forces. In addition, the assembly of the conventional alarm horn 10 requires much time and labor because of the use of such separate component parts.